Synthetic oil addition agents



Patented Oct. 28, 1941 SYNTHETIC OIL ADDITION AGENTS Ernest EEngelke, Merchantville, N. .l., assignor to Cities Service Oil Company, New York, N. Y., a corporation of Pennsylvania No Drawing. Application September 15, 1939, Serial No. 295,037

11 Claims.

, This invention relates to oil products containing and improved by the presence therein of certain organic halogenated phosphine compounds.

Organic phosphine compounds have been added to lubricating oils and other preparations for various purposes, as for example, Butz has proposed the use of phosphine oxides and sulfides in his Patent No. 2,138,835, as addition agents for lubricating stocks. These were proposed particularly for increasing the extreme pressure characteristics of the 011 stocks.

A number of investigators have also found that certain phosphorus compounds successfully inhibit the corrosion of certain of the bearing alloys used in automobile'engines. Such bearings as cadmium-silver, cadmium-nickel and copperlead have been found to be more or less readily corroded by the usual motor oils, particularly those oils made by solvent extraction processes.

Addition agents which inhibit corrosion therefore are of considerable advantage, not only because they prevent or reduce corrosion of motor bearings, but because they tend to prevent deterioration of the motor oils from the catalytic effects of the metals with which they come in contact.

vention is to provide new and useful organic halogen-containing phosphine compounds which will improve motor oils and other lubricants, prevent deterioration of the oil and inhibit corrosion of the motor bearings.

contain no nitrogen because phosphine-nitrogen derivatives such as amino compounds are as a The primary object therefore of the present intached through an oxygen or surfur atom as in the case of alcohols, phenols, mercaptans and thiophenols. The preferred compounds furthermore contain at least one halogen atom, directly attached to phosphorus, and an oxygen or a sulfur atom, also directly attached to phosphorus (by a double bond).

The method of making the improved addition agents of the present invention may be illustrated by describing the steps used in the making of a di-cresol chlorophosphine sulfide. One mol of phosphorus tri-chloride is reacted with two mols of a cresol (or mixture of cresols) at ordinary room temperature until the evolution of hydrochloric acid gas substantially ceases, after which the mixture is heated on a steam bath to complete the reaction. The resulting product'is a di-cresol mono-chlorophosphine which is purified by distillation at a low pressure of from 1 to 2 mm. of Hg. A satisfactory purification however consists in topping oi the light material to a temperature of about 400 F. at 11- mm. of Hg. The sulfide may be readily produced by, reacting the di-cresol mono-chlorophosphine with one equivalent of sulfur at a temperature of from 360 to 380 F. The resulting product is a dicresol mono-chlorophosphine sulfide. The phosphine oxide may be produced by treating the dicresol mono-chlorophosphine with hydrogen peroxide or nitric acid to oxidize the phosphine to the phosphine oxide. The di-chlorophosphine rule very difficult to dissolve in mineral oils, or

to beheld in solution once they have been dis-' solved under favorable conditions, such as at much higher temperatures than are employed in their use. The halogenated phosphine compoundsof the present invention contain at least one organic radical such as an alkyl, aryl, aralkyl, hydroaryl or a heterocyclic radical. Such .radicals may be directly attached to the phosphorus through a carbon atom but are preferably atderivatives may be made by reacting one mol of phosphorus trichloride with one mol of the desired organic compound such as a phenol or a thiophenol.

The phosphine sulfide produced by the above procedure may be purified by digestion with strong caustic soda and thereafter washing it with water, whereupon the product when recrystallized from alcohol has a melting point of from to F. When the products are made from mixed organic compounds such ,as mixed phenols or cresols, they have a very indefinite melting point and tend to remain in liquid state I The improved addition agents of the present invention may be used alone as a film strength' agent or mixed with any grade of lubricating oil. liquid hydrocarbon, mineral oil or ofly or grease compositions. The organic radicals or groups in any one of the halogenated phosphine derivatives may be alike or different, and one or more such groups may contain separate halogen atoms. The presence of chlorine or other halogen atoms such as fluorine, bromine and iodine, has been found to effectively increase the film strength characteristics of such compounds. Each of the organic groups or radicals also preferably contains at least six carbon atoms, although such radicals containing less than six atoms of carbon in certain cases possess merit.

Examples of specific compounds used as addition agents in accordance with the present invention are:

Di-phenol-O-mono-chlorophosphine oxide Di-cresol-O-mono-chlorophosphine oxide Di-butyl mono-chlorophosphine oxide Di-amyl mono-chlorophosphine oxide Di-benzyl mono-chlorophosphine oxide Mono-phenol-O-di-chlorophosphine oxide Mono-cresol-O-di-chlorophosphine oxide Mono-butyl di-chlorophosphine oxide None-benzyl di-chlorophosphine oxide Di-phenol-O-mono-chlorophosphine sulfide Di-ortho, meta and para cresol-O-mono-chlorophosphine sulfide Di-butyl mono-chlorophosphine sulfide Di-benzyl mono-chlorophosphine sulfide Di-thiophenol-S-mono-chlorophosphine sulfide Di-ortho, meta and para thiocresol-S-mono chlorophosphine sulfide Di-thiobutyl-S-mono-chlorophosphine sulfide Di-thiobenzyl-S-mono-chlorophosphine sulfide Di-thienyl-S-mono-chlorophosphine sulfide Dithiophenol-S-mono-chlorophosphine oxide Di-ortho, meta and para thiocresol-S-monochlorophosphine oxide Di-thiobutyl-S-mono-chlorophosphine oxide Di-thiobenzyl-S-mono-chlorophosphine oxide Di-thienyl-S-mono-chlorophosphine oxide Di-hydroxybutyl-O-mono-chlorophosphine oxide Di-hydroxybutyl-Omono-chloroplmsphine sulfide Mono-hydroxybutyl-O-di-bromophosphine oxide Mono-hydroxybutyl-O-di-bromophosphine sulfide The S- and -O- symbols used in the foregoing list of compounds indicate the fact that the organic groups are attached to phosphorus through the oxygen and sulfur atoms in the organic group.

The compounds of the present invention are eflective for preventing or inhibiting the corrosion of various bearing metals such as those used in automobile motors. This effectiveness may be illustrated by comparison of the results of tests made on certain bearing metals with a Pennsylvania lubricating oil of S. A. E. 20, and this same oil containing an added compound. The oil alone showed substantial corrosion of bronze-' babbitt and cadmium-copper-silver alloys, but from 1% to 1.5% of di-phenol-O-mono-chlorophosphine oxide and of di-paracresol-O-monochlorophosphine sulfide in the oil substantially inhibited corrosion in each instance.

Tests were also carried out to determine the effect of the halogenated phosphine compounds of the present invention in decreasing engine bearing wear with respect to various types of bearing alloys. Tests were conducted on the alloys: cadmium copper silver, copper lead. bronze-babbitt and babbitt, all of which were very substantially worn by the use of a 20 8. A. E. solvent treated oil which contained no addition agent. The same was true with a Pennsylvania 20 S. A. E. oil not produced by solvent extraction, although the corrosion for babbitt was somewhat less. The wear was very greatly decreased with both types of oil containing 0.5% of di-cresol-O-mono-chlorophosphine sulfide.

Further tests were also made to determine the film strength of the oil alone and the oil containing addition agents prepared in accordance with the present invention. The 20 S. A. E. Pennsylvania motor oil alone had a load carrying capacity on the Timken testing machine of 8700 lbs. per square inch with the machine operated at 500 R. P. M. and a rubbing speed of 250 feet per minute, at a temperature of F. Comparative tests on the same oil containing 0.5%, 1.0% and 1.5% of di-phenol-O-mono-chlorophosphine sulfide showed load-carrying capacities respectively of 11,000, 14,400 and 18,300 lbs. per square inch. These same proportions of dipara-cresol O mono-chlorophosphine sulfide showed load carrying capacities respectively of 14,200, 18,000 and 19,200 lbs. per square inch.

While the foregoing examples illustrating the properties and applications of the improved compounds relate primarily to their use in mineral oils, it is to be understood that the inventionincludes their use as such or in any mixtures for all purposes to which they are adapted. A mixture of two or more compounds may be used as an addition agent. For example, they have been found useful in cutting oils and in lubricants for the bearings and cylinder wall surfaces of internal combustion engines. The compounds may also be used as anti-rust agents, film strength agents in greases, and in blends cont-aining fatty oils, synthetic oils and esters, or they may be used alone as film strength agents for any desired use where the maintenance of a surface film between moving parts of a mechanism is essential.

The improved compounds of the present invention have been found particularly useful in the crank case of an automobile, since in a lubricant vehicle they maintain a relatively clear oil over substantially long periods of use. The compounds are also effective ingredients of crank case flushing compositions because they aid in dissolving resinous constituents in the motor and crank case and at the same time provide an efiective lubricant in light oil solvents or mixtures. Flushing oils therefore containing such compounds may be used in a motor operated for substantial periods of time while the crank case is being cleaned and flushed. A suitable flushing mixture may contain from 1% to 5% of one or more of the compounds, dissolved in relatively large proportions of light oils such as kerosene, light furnace 011, light coal tar distillates or mixtures of these oils.

The phosphine compounds of the present invention may be used as top cylinder lubricants in internal combustion engines by adding approximately 1% by volume thereof to the motor fuel to be used in the engine. The improved phosphine compounds may also be employed for other purposes as will be apparent to those skilled in the art.

Having thus described the invention in its preferred form, what is claimed as new is:

1. A composition of matter comprising a lubricating oil containing a relatively small proportion of a nitrogen-free organic chlorophosphine oxide in which chlorine is directly attached to phosphorus.

2. A composition of matter comprising a hydrocarbon oil containing approximately 1% of a nitrogen-free organic chlorophosphine oxide in which chlorine is directly attached to phosphorus.

3. A composition of matter comprising a hydrocarbon oil and a relatively small proportion of a nitrogen-free di-cresol-O-mono-chlorophosphine oxide in which the chlorine is directly attached to phosphorus.

4. A composition of matter comprising a hydrocarbon oil containing a relatively small proportion of a,cresol-O-chlorophosphine sulfide in which chlorine is directly attached to phosphorus.

5. A composition of matter comprising a hydrocarbon oil and a relatively small proportion of an organic halogenated phosphine oxide inwhich the halogen is directly attached to phosphorus and in which each organic radical contains at least six carbon atoms.

6. A lubricant comprising a hydrocarbon oil and a halogenated phosphine oxide in which a halogen is directly attached to phosphorus and which contains an organic radical directly attached to pho horus and selected from the group consistin of alkyl, aryl, hydroxyalkyl,

haloalkyl, haloaryl, hydroxyaryl, phenolic, mercapto,- thiophenolic, aralkyl, hydroaryl and heterocyclic groups.

'7. A lubricant comprising a hydrocarbon oil and a relatively small proportion of a compound selected from the group consisting of nitrogenfree organic halogenated phosphine oxides and sulfides in which halogen is directly attached to phosphorus.

8. A composition of matter comprising a hydrocarbon oil containing a relatively small proportion of a nitrogen-free di-cresol-O-chlorophosphine sulfide in which chlorine is directly attached to phosphorus.

9. A composition oi-matter comprising a hydrocarbon oil containing a relatively small proportion of a di-thio-phenol-S-chlorophosphine oxide in which chlorine is directly attached to phosphorus.

10. A composition of matter comprising a hydrocarbon oil and a small proportion of a compound selected irom the group consisting of nitrogen-free organic halogenated phosphine oxides and phosphine sulfides in which halogen is directly attached to phosphorus.

11. A composition of matter comprising a hydrocarbon oil and a relatively small proportion of a nitrogen-free compound selected from the group nsisting of organic halogenated phosp oxides and phosphine sulfides and mixtures thereof in which halogen is directly attached to phosphorus, and wherein each organic radical in the compound consists of a radical containing at least six carbon atoms and selected 'from the group consisting of alkyl, aryl, aralkyl,

hydroaryl, heterocyclic, hydroxyalkyl, hydroxyaryl, phenolic, mercapto, thiophenolic, haloalkyl and haloaryl radicals.

ERNEST F. ENGELKE. 

